Squirrels

Squirrels are rodents in the family Sciuridae: bushy-tailed tree squirrels, burrowing ground squirrels and gliding flying squirrels. They eat mostly nuts, seeds, fruit and buds, don't hibernate (tree squirrels), very rarely carry rabies, and become pests mainly when they raid bird feeders and gardens or nest in attics.

Most of the time a squirrel is just backyard scenery. This page covers types, diet, lifespan and breeding, and the signs that one has moved into your house.

Types of squirrels in the US

Tree squirrels

• Eastern gray squirrel (Sciurus carolinensis): the most familiar squirrel in eastern and midwestern towns, also introduced on the West Coast. Gray with a white belly; black and white color forms occur.
• Fox squirrel (Sciurus niger): larger (up to about 2 pounds), rusty orange-brown belly, common in the Midwest, South and many western cities.
• American red squirrel (Tamiasciurus hudsonicus): small, reddish, loud and territorial; northern and mountain conifer forests.
• Western gray squirrel (Sciurus griseus): Pacific states, silvery with a very bushy tail.
• Flying squirrels (northern and southern, Glaucomys): small, nocturnal, glide on furry skin flaps between legs. Often colonize attics in groups without the owner ever seeing them.

Ground squirrels

• California ground squirrel, Richardson's, thirteen-lined and others: burrowing squirrels of the West and Great Plains, serious pests in farms, orchards and yards. Chipmunks, prairie dogs and groundhogs are close relatives.

Are squirrels rodents?

Yes. Like rats and mice, they have four chisel-like front teeth that never stop growing, which is why squirrels chew on wood, wiring, siding and plastic.

What do squirrels eat?

Tree squirrels are mainly plant eaters:

• Nuts and seeds: acorns, hickory nuts, walnuts, pecans, beechnuts, pine seeds
• Tree buds, flowers and bark in spring
• Fruit and berries; garden tomatoes, corn, squash and strawberries
• Fungi (mushrooms and truffles)
• Bird seed, especially sunflower and corn
• Bulbs: tulips and crocuses (they mostly leave daffodils alone)

Do squirrels eat meat? Sometimes: insects, bird eggs, nestlings, and occasionally carrion. What squirrels like to eat most is high-fat, high-calorie food: nuts and black oil sunflower seed.

What can squirrels eat safely if you want to feed them? Unsalted nuts in the shell, fresh vegetables and fruit in small amounts. Feeding is discouraged, because it concentrates squirrels around your house; and avoid bread, salted or sugary foods.

They bury nuts in fall in hundreds of scattered caches (gray and fox squirrels) or one large midden (red squirrels), and they forget many of them, which plants oak and walnut trees.

Do squirrels hibernate?

Tree squirrels: no. They're active all winter, though they may stay in the nest for a day or two during storms or deep cold, living on cached food and body fat.

Ground squirrels: many do. California ground squirrels may go dormant in hot summers (estivation) and in cold winters; thirteen-lined and Richardson's ground squirrels hibernate for months.

Where do squirrels sleep?

• Leaf nests (dreys): football-sized balls of leaves and twigs in tree forks, 30 feet up or more.
• Tree cavities: woodpecker holes and hollows, preferred in winter and for raising young.
• Attics, wall voids and chimneys: a warm, dry substitute for a tree cavity.
• Burrows for ground squirrels.

When do squirrels have babies?

Gray and fox squirrels have two breeding seasons:

• Mating in December-February, babies born February to April.
• Mating in May-June, babies born July to September.

Litters are usually 2-5. Babies are born hairless and blind, open their eyes at about 4-5 weeks and leave the nest at 10-12 weeks. These two windows are exactly when attic invasions peak and when you must not seal a squirrel out without checking for babies.

How long do squirrels live?

Most wild tree squirrels die in their first year. Those that survive average about 2 years, and some live 6 years or more. In captivity they can live 10-20 years. Hawks, owls, cats, cars and power lines are the main causes of death.

How do squirrels land when they fall?

On their feet. They twist their body in the air, spread their legs and use the tail as a parachute and rudder, and their light weight means they can survive falls that would injure larger animals.

Do squirrels have rabies?

Rarely, and CDC says small rodents such as squirrels, chipmunks, rats and mice are almost never found to be infected and have not been known to transmit rabies to people in the US. Larger rodents like groundhogs are the exception. A squirrel bite can still get infected; wash it with soap and water and see a doctor if it's deep or red. Squirrels can carry fleas, ticks and mites.

Squirrels in the house: signs

• Scurrying, scratching and rolling sounds in the attic or walls in the early morning and late afternoon (flying squirrels: at night; rats and mice are also night-time, see signs of mice)
• A chewed hole 1.5-3 inches across at a roof corner, soffit, fascia, gable vent or roof vent
• Chewed wiring (a fire risk), torn insulation, nesting material
• Squirrels running along power lines and branches to your roof

Are squirrels pests?

They can be: chewed wiring and wood, attic nests, raided bird feeders and gardens, dug-up bulbs and pots, and ground squirrel burrows that undermine slopes and foundations in the West. For what to do, see how to get rid of squirrels. For other attic visitors, compare raccoons and bats.